Abstract

The process of dye photodestruction in a solid-state dye laser is
studied, and implemented is a polymeric gain medium doped with a
strongly concentrated dye. The behavior of the conversion
efficiency in the polymeric gain medium pumped with different
laser-pulse repetition rates and the process of dye photobleaching are
analyzed. The contribution of the heating of the host material into
the dye molecules’ deactivation is discussed. The negative effect
of high dye concentration on the dye stability under a high pump
repetition rate is reported and analyzed for the first time to my
knowledge. A comparison of the present results with recently
published data demonstrates the major role of photodestruction, rather
than direct thermodestruction, in the dye stability of the solid-state
gain medium. The role of additives with low molecular weights in
the polymeric matrix, for increasing the stability of the gain
material, is discussed.

Although it is customary in the literature to use the term photodestruction, it would be more suitable to use photodegradation or photobleaching (i.e., losing excitation-radiation properties) instead. Indeed, no direct physical destruction of dye molecule bonds takes place under photoexcitation in the lasing medium, but reconfiguration of the conjugated electronic shells responsible for radiation does occur. This reconfiguration leads to an aggregation of dye molecules into higher oligomers or to chemical reactions that destroy the dye molecules. However, we follow the tradition and use the term photodestruction.

Opt. Quantum Electron. (1)

Other (7)

Although it is customary in the literature to use the term photodestruction, it would be more suitable to use photodegradation or photobleaching (i.e., losing excitation-radiation properties) instead. Indeed, no direct physical destruction of dye molecule bonds takes place under photoexcitation in the lasing medium, but reconfiguration of the conjugated electronic shells responsible for radiation does occur. This reconfiguration leads to an aggregation of dye molecules into higher oligomers or to chemical reactions that destroy the dye molecules. However, we follow the tradition and use the term photodestruction.

Photobleached areas pumped with the 4- and 10-Hz
repetition rates as they are seen (a) on the whole surface and
(b) on the enlarged fragment of the gain sample. The framed
image in (b) was processed with a color contrast–brightness ratio
enhancement to highlight the change of the optical density of the
material.